This department is the first step of the dentistry to plan the treatment of a patient who has the problem of oral and dental health and to determine the symptoms. Dentistry is a branch examining the tooth; gingival tissues; and diseases, abnormalities and defect developments in the mouth; as well as researching prognosis and treatment criteria, and planning the treatment of all patients who has any problem with mouth and tooth health. This branch benefits from different laboratory methods for the final diagnosis of a disease like general medicine. Dentistry radiology is also one of the sub-branches in the dentistry. Aim of this sub-branch is to find the source of prior complaints of patients. Current situation of a patient is handled as a whole, so by determining not only current complaints but also the sections that may create possible problems in future, you can lead the patient to the treatment before the complaint proceeds. By this way, protective and preventive treatments applied by early diagnosis prevent bigger problems in future and make the treatment simple and economic.

Oral and Maxillofacial Radiology: It is a branch of Dentistry that makes diagnosis of the diseases in the mouth, tooth and jaws; and determines the possible clinical or radiological treatment methods. It is aimed to determine and evaluate radiographies taken from the parts of mouth, tooth, and jaw and if available pathology and anomaly. In the light of information obtained from them; treatment plans unique to the individual are prepared and patients are directed to the expert clinics where these treatments will be applied. There are different types of roentgen used in Dentistry.
These are divided into two: 1- Intraoral, 2- Extraoral . Dental radiographies are the most useful facilitators for the field, in other words tooth films, in diagnosis of the intraoral diseases especially those related to the hard tissues such as tooth and jaw bones.

The two commonly used tooth films are periapical (small films showing 2-3 teeth) and panoramic films (big films showing teeth and jaw bones totally). Use of radiography machines which is a computer aided technique makes it possible for us to make detailed evaluations by imposing luminous effects on film photographs through low radiation doses. In addition to the mentioned films, MRI and CT may also be requested especially in implant applications and in diagnosis of joint diseases.
1-Diagnosis of symptoms
2-Diagnosis of syndromes
3- Methods of diagnosis
4- Detection of laboratory-radiological-pathological practices/methods that leads to diagnosis

Dentistry is not always limited to oral diagnose data. Some of the intraoral symptoms may be systematic, common and they may be the indications for serious diseases. For example; gingival bleeding is not only the indication of a syndrome of teeth but also the indication (symptom) of serious diseases such as Leukema. Mouth cancer constitutes five per cent of the all cancer types; and therefore a dentist is supposed to have knowledge of a good Oral Diagnose for early diagnosis.